1. Field of the Invention
With regard to the classification of art, this invention is believed to be found in the general class entitled SIGNALS AND INDICATORS and more particularly to those subclasses pertaining to those that are CHEMICALLY ACTIVATED.
2. Description of Related Art
Useful life indicators are known in the prior art. One example in the known prior art is U.S. Pat. No., 4,812,053 which issued to Bhattacharjee on Mar. 14, 1989. This cited patent has advanced the art but accuracy, repeatability and reliability still remain an identified need. The present invention addresses those above identified needs. The present invention provides a structure that allow at least one of its indicating portions to remain dormant from the time of manufacture until the time of activation. After activation, the present invention provides an indication means that is activated by a component of an ambient fluid. This present invention also includes a membrane member which protects the indicator material.